This invention relates to the manufacture of gasified solid fusible sugar products and more particularly to a novel continuous process for concentrating an aqueous sugar solution and introducing gas into the resultant fused concentrated sugar composition. Solidification of the gasified fused sugar composition produces a gasified solid product.
Kremzner et al. U.S. Pat. No. 3,012,893 describes a technique for enclosing a gas within a solid matrix of fusible sugar in which a sugar melt is prepared and placed in a Parr reactor wherein it is maintained in a fused condition while carbon dioxide gas is admitted and the mixture agitated with a stirrer. This patent gives limited details on the process but, to the extent described, the process of Kremzner et al. is entirely a batch operation. Subsequent Pat. Nos. of Kirkpatrick 3,985,909, Kirkpatrick 3,985,910 and Hagedorn 4,001,457, each issued to the assignee of the Kremzner et al. patent, describe refinements to Kremzner et al. method for producing a carbonated candy product. In each of these references, however, the process described remains an entirely batch process in which gas is introduced into the headspace of an autoclave containing a fused sugar composition and mixed by stirring of the contents in the autoclave. Kirkpatrick '909 describes an improvement in which the shaft of the stirrer or agitator has a hollow interior with sidewall openings at each end so that mixing is assisted by the passage of gas through the shaft, exiting at the bottom thereof for dispersion by rotating paddle blades mounted on the shaft.
In the batch processes described in the aforesaid references, mixing requires stirring for a significant period of time, during which the melted sugar is exposed to temperatures in the range of 300.degree. to 325.degree. F. Such exposure can lead to both the production of invert sugar by hydrolysis of sucrose and to browning of the sugar composition due to thermal degradation thereof. Inasmuch as the gas component is simply introduced into the headspace of an autoclave filled with an amount of melted sugar that is determined primarily by payload and agitation considerations, there is no positive control over the relative proportions of gas and liquid and, consequently, no positive control over the gas content of the gasified sugar product. Additionally, the productivity of the batch process is limited by the significant mixing time requirement as well as by the autoclave charging and discharging operations which are necessary parts of the batch cycle but constitute dead time so far as the gasification operation is concerned. Moreover, the processes heretofore known to the art have not been adapted for the incorporation of volatile or thermally sensitive additives such as, for example, certain natural flavors and colors. There is thus a need in the art for an improved process for producing gasified solid sugar products, and particularly for an improved process which is adapted to overcome the various limitations which are experienced with the batch processes described in the aforesaid references.